This application is a U.S. national application of PCT/NL96/00193, filed on May 3, 1996.
The present invention is relates to printing of images in general and, more particularly, to methods for printing multi-page images.
Electronically based printing can be divided into three parts. In the first part an image, which may consist of text only, images only, line drawings only or any combination of text images or line drawings is formed into an text or combination text and image file. In general, long files require more than one page for printing and the files represent more than one page of text and/or image.
When this information is to be directly printed from the application which generates the file, the application paginates the file and sends it to the printer in a form which the printer can use, for example in the form of a bit map or other such form.
In the preparation of films for offset printing a number of pages are generally printed at the same time on a large sheet in a mutual orientation suitable for subsequent folding and slitting in the manufacture of a multi-page document such as a book or magazine. Moreover, it is customary to treat each such multi-page sheet as a single file. When the film is to be generated, the multi-page file is transformed into a bit mapped image which is used to expose the film. Similarly, when printing is direct, i.e., without an intermediate film, the entire file is bit-mapped together for printing.
Thus, if one page of a multi-page file is to be changed, the entire file must be remapped, a rather time consuming process.
WO 95/02224 discloses a system for making up pages in which bit-mapped sub-page elements are stored in a memory and are organized into a page prior to printing.
The present invention seeks to provide a system in which the delays and down time associated by last minute changes are reduced or eliminated.
This is accomplished by generating a separate set of files, designated collectively herein as a xe2x80x9cpage filexe2x80x9d for each page from image data provided by an application such as page make-up software or word processing and postscript type applications. The page file may include color separations for the various colors to be printed on the page or other convenient forms of storage devoted to a single page. The page file may be in a bit mapped format or may be in the form of a continuous tone image in a format which can be easily converted into a bit-map format by the printer during the printing process. Preferably, the continuous tone image can be converted into a bit map for printing on the fly.
There is thus provided, in accordance with a preferred embodiment of the invention, a method of printing a multi-page job comprising:
producing separate non-bit mapped files for each page of the multi-page job;
producing a page file for each page of the multi-page job;
storing the page files in a memory; and
printing the page files in sequence.
In a preferred embodiment of the invention the method includes:
producing at least one replacement non-bit mapped file for one of the pages of the multi-page job to replace one of the pages for which a page file has been previously generated;
producing a replacement page file for the replacement page; and
storing the replacement page file in the memory,
wherein the replacement page file is printed in the sequence in place of the page being replaced.
There is further provided, in accordance with a preferred embodiment of the invention, a method of preparing a a multi-page job for printing comprising:
producing separate non-bit mapped files for each page of the multi-page job;
producing a page file for each page of the multi-page job;
storing the page files in a memory;
producing at least one replacement non-bit mapped file for one of the pages of the multi-page job to replace one of the pages for which a page file has been previously generated;
producing a replacement page file for the replacement page; and
storing the replacement page file in the memory.
Preferably, the method further comprises:
printing the multi-page file with the replacement page replacing the page which has been replaced.
In one preferred embodiment of the invention, the page file comprises at least one bit mapped image of the page. In a second preferred embodiment of the invention, the page file comprises a continuous tone file adapted for on-the-fly conversion to a bit map during printing.
In a preferred embodiment of the invention the page file is stored in compressed form in the memory.